A sample of 312 low-frequency-peaked BL Lacertae objects (LBLs) and 694 flat-spectrum radio quasars (FSRQs) with the parameters of both redshift and gamma-ray photon spectral index ({Gamma}{gamma}) is compiled from the Fourth Catalog of Active Galactic Nuclei Data Release 2 from the Fermi Large Area Telescope (LAT). The multiwavelength data of the sample sources are downloaded from the Space Science Data Center, and then matched to the corresponding gamma-ray data from the Fermi-LAT Fourth Source Catalog DR2. The synchrotron radiation peak frequency and Compton dominance (CD) parameters of the sources are obtained by using a log-parabolic model to fit the average-state multiwavelength spectral energy distribution. A support vector machine in the logL_{gamma}-{Gamma}{gamma} frame is utilized to delineate the optimal boundary between FSRQs and LBL sources. The 1{sigma} position of the Gaussian fitting on the histograms of the {Gamma}{gamma}, log{nu}_peak^syn^, and CD parameter distributions are also introduced. With this criterion, 25 FSRQ candidates are selected from LBL sample sources. The optical spectral identification result confirms that 8 out of 13 candidate sources available with the optical spectral data exhibit the relationship of EW>5{AA}.

Cone search capability for table J/ApJS/278/11/sample (Logarithmic parabola fitting results for BL Lacertae objects (LBLs; Table 1) and flat-spectrum radio quasars (FSRQs; Table 2))